The more than 2000 mostly elderly South Australians still using a 3G Personal AlertSA device have been urged to upgrade their equipment before the outdated mobile network is switched off.

Telstra was due to shut off it's 3G coverage from 1 July but this week announced it would keep the network running until the end of August, however the provider is urging customers to update their devices as quickly as possible.

The upcoming network shutdown will not only impact mobile phones but also personal and medical alert devices – such as pendants and call button devices, which allow a person to quickly and easily send for help in the event of an emergency such as a fall.

Older devices reliant on 3G technology will stop working after the shutdown.

Customers of Personal AlertSA, a State Government program that funds or subsidises devices and monitoring for eligible older people, can access support to upgrade to a 4G device – including options with no out-of-pocket cost.

About 11,000 South Australians are enrolled in Personal AlertSA and while most are now using 4G devices, there are still more than 2200 customers that have yet to transition their device.

These people are urged to call the Personal AlertSA hotline on 1300 700 169.

People who access their personal alert devices from private providers or Commonwealth-supported programs are strongly urged to contact their system provider for support before the 3G network is cut-off.

Alert user Fil (pictured) is one of the many South Australians who will have to update her device to a 4G model, and she encouraged others to do the same.

"It is very important to me - because I'm dangerous!" she said with a laugh.

"I carry it with me all the time. The moment I don't carry it, something happens. I've had four falls - I rely on this thing a lot."

Fil said she believed her device was, quite literally, a lifesaver.

"There was one fall I had in the bathroom," she said.

"I just collapsed, I don't know what happened.

"If I didn't (have it) I'd be lost. I don't think I would've made it to this day."

Council on the Ageing deputy chair Anne Burgess AM said personal alert devices helped older people to feel more confident and safer in their own homes.

“Don’t risk having one that doesn’t work just when you need it,” Ms Burgess said.

“If you’re not sure what network you’re on or how to move to 4G call 1300 700 169 and someone can help you.

“If you have a family member or know someone who uses a personal alert device, please encourage them to check their device and their network.”

For more information on Personal AlertSA and eligibility, go online here or phone 1300 700 169 (Monday to Friday, 9am to 5pm).